28778403 has 4 divisors (see below), whose sum is σ = 38371208. Its totient is φ = 19185600.

The previous prime is 28778389. The next prime is 28778419. The reversal of 28778403 is 30487782.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 28778403 - 2¹³ = 28770211 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28778003) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4796398 + ... + 4796403.

It is an arithmetic number, because the mean of its divisors is an integer number (9592802).

Almost surely, 2^28778403 is an apocalyptic number.

28778403 is a deficient number, since it is larger than the sum of its proper divisors (9592805).

28778403 is an equidigital number, since it uses as much as digits as its factorization.

28778403 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9592804.

The product of its (nonzero) digits is 75264, while the sum is 39.

The square root of 28778403 is about 5364.5505869551. The cubic root of 28778403 is about 306.4471334970.

The spelling of 28778403 in words is "twenty-eight million, seven hundred seventy-eight thousand, four hundred three".